Method and apparatus for depositing film on a substrate, and products produced thereby

ABSTRACT

Method and apparatus for using emitting, ionizing, accelerating and collecting elements in a high vacuum to implant a hard film on a plastic substrate or the like. In preparation, a slug of a selected material to be deposited as a film is placed in the emitter. The specimens or articles to be implanted are placed on supports in the vicinity of the collector. A cover enclosure is then placed in position and the region enclosed by the cover is exhausted to a high vacuum. Selected potentials are applied to various elements of the apparatus and an accelerating/directing field which may be developed electrostatically, magnetically or by a combination of both, is developed in the acceleration structure. The electrostatic field causes electron emission from the ionizing elements to develop an increased charge on the emitted ionized particles. When implantation is to begin, a shutter control is moved out of beam blocking position and ionized particles from the emitter pick up additional charge from the ionizing elements and are accelerated to high velocity for bombarding the specimens. The collector is provided near the end of the enclosure beyond the specimen support region. The specimens are discharged regularly to eliminate the build-up of surface charge from the stream of bombarding ions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of co-pending application Ser. No.571,480 of Joseph E. Berg et al for METHOD AND APPARATUS FOR DEPOSITINGFILM ON A SUBSTRATE AND PRODUCTS PRODUCED THEREBY, filed Apr. 24, 1975,granted under U.S. Pat. No. 4,107,350, which was a division ofapplication Ser. No. 280,489, filed Aug. 14, 1972, now U.S. Pat. No.3,913,520.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to film deposition methods and apparatus, andmore particularly, to such apparatus and methods for depositing a thintransparent hard film on a substrate, the properties of which may beenhanced by transformation of its surface in such manner. The inventionis particularly applicable to film implantation in plastics.

2. Description of the Prior Art

With the increasing use of plastic and other non-glass lenses ineyeglasses and other items, it has become increasingly important todevelop hardened surfaces on such relatively soft materials which resistscratching and abrasion. This is particularly true since the recentintroduction of laws requiring the discontinuance of glass lenses in allbut a few types of eyeglasses. Various methods of developing suchhardened surfaces have been employed, but with less then completesuccess. These methods include the dipping of plastic lenses, the wipingon of a film, the use of harder plastics themselves, the provision of alaminated lens and similar approaches. Ideally, of course, such aproduct should have the resilience of the better plastics for protectionagainst impact from hard objects while having surfaces that are aseffective as glass or more so in resisting scratching and abrasion.

Similarly the surface properties of many materials and objects may beenhanced by the provision of an extremely thin surface coating of asuitable material which may serve to protect the surface underneath fromcorrosion, wear and the like or provide a surface hardness notattainable by the substrate alone. Thus for example, razor blades whichare said to suffer more from corrosion than wear, may be made to lastmany times longer than at present with suitable protection of the finecutting edge from corrosion. If at the same time the cutting edge may behardened, then the effects of wear will be reduced as well, both factorsacting together to provide a much longer lasting blade.

In addition, surface alloys may be developed on metal substrates andsurface layers of various dopings of impurities and the like onsemiconductor substrates may be possible through the use of appropriatedeposition and implantation techniques. The accomplishment of suchdevelopments would greatly economize on the use of rare and expensivematerials where only surface effects are needed.

Efforts have been made to develop such products by particle bombardment.Examples of such may be found in U.S. Pat. Nos. 3,117,022 of G. A.Bronson et al, 3,494,852 of M. Doctoroff, 3,371,649 of H. E. T. Gowen,3,409,529 of K. L. Chapra et al, 3,472,751 of W. J. King, 3,562,141 ofJ. R. Morley, and others. However, whether through ineffective focusingor direction of the beam, emission and control of the ionized particlesof for whatever reason unknown, such approaches have not resulted intruly acceptable and satisfactory products which realized the potentialof the theories underlying such bombardment techniques.

SUMMARY OF THE INVENTION

The invention is generally set forth in the abstract above, which isincorporated by reference. In brief, the invention comprises methods andapparatus for developing emission of ionized molecular particles of aselected material and further ionizing the particles and acceleratingthem in a predetermined path toward a collector region for implantationon a plastic or other substrate positioned in the vicinity of thecollector region. The entire particle bombardment structure ispositioned within a vacuum chamber during operation. Predeterminedelectrical potentials are maintained at the various elements of thestructure employed in the apparatus. Either electrostatic or magneticion beam directing apparatus may be employed for beam control or somecombination of the two systems may be utilized. An electrostatic fieldis required, however to develop electron emission from ionizing elementspositioned adjacent the path of the beam so as to "super-ionize" thebeam, thus permitting effective acceleration. The beam is directed overa sufficient extent and controlled to such a degree by apparatus inaccordance with the invention as to permit bombardment of specimensubstrate over a considerable area. Where the specimen substrate isnon-conducting, provision is made for the dissipation of surface chargecarried to the substrate by the bombarding ions. Those ionized particleswhich do not impact the specimen materials are caught on a collectinggrid and removed from the system.

Material which has been successfully implanted in apparatus inaccordance with the invention comprises minerals such as are set forthin the above-identified patents, selected for their properties ofhardness, elasticity, heat resistance and optical clarity. The materialsmay include trace amounts of minute impurities such as may be found incommercial grade materials. In one example these materials are implantedonto various types of plastic lenses with implantation occurring to adepth of approximately 10,000 Angstroms (1 micron) within the preferredrange from several hundred Angstroms to a few microns and the process ofimplanting and depositing continuing until a film layer is built up to apreferred thickness of approximately 2 microns. The result is aneyeglass lens or other product which has the shatter-resistance of theplastic substrate under the surface film with abrasion-resistantproperties equal to or better than those of glass.

In one particular arrangement in accordance with the invention, anelectron beam gun emitter was employed with a paste mixture of suchknown minerals selected for their properties of hardness, elasticity,heat resistance and optical clarity, positioned in the electron beam guntarget region. This electron beam gun is water-cooled, has a filamentfor emitting electrons and utilizes electromagnetic fields to cause theemitted electron beam to curve and bombard the target material. As aresult, the target material and its molecules are bombarded off thesurface as ionized molecular particles where they become accelerated bythe field of the particle accelerator. A removable shutter is positionedin the region between the emitter and the accelerator to block or passthe beam as desired.

The accelerator structure has interspersed ionizing elements whichfurther ionize the molecular particles of the beam. This structureaccelerates, directs and shapes the beam in its path to the specimen andcollector region. In one particular arrangement of the invention, theaccelerator structure comprises a series of spaced and insulated flatrings of varying diameters, increasing in the direction of beamtraversal. Selected ones of these rings were fashioned as ionizingelements by silver soldering sharp needles with their points directedinward and generally equally spaced about the circumference of therings. These sharp points serve as electron emitters for furtherionizing particles as they pass through the rings. The acceleratorstructure is suspended from insulated wires extending to a supportstructure which also holds a target frame on which various lenses may bemounted. The collector screen extends over the specimen supportbrackets, physically and electrically separated therefrom, and ispositioned across the divergent beam region so as to collect thoseparticles that do not impact the specimens.

In operation, a bell jar type cover is placed over the entire structureand the region thus enclosed is evacuated to a high vacuum. Theinsulators and interconnecting conductors are arranged to developvarious potentials at various elements of the structure. A DC powersupply has been employed for developing these potentials with selectedRF modulation of certain electrode elements being developed from an RFgenerator.

In one preferred arrangement in accordance with the invention, theelectron beam gun emitter is maintained at the negative power supplyvoltage which is 10 kv. The first, third and fifth rings of theaccelerator structure (counting from the bottom nearest the electronbeam gun emitter) are preferably maintained at neutral potential,although these may have their potentials controlled, if desired, toexert minor control on the particle beam. The second and fourth ringsare the ionizing elements with the needles attached. These aremaintained at a negative potential range of approximately -3,000 to-15,000 volts, modulated with an RF signal of approximately 25 to 100volts rms at 400 megahertz. The sixth and final ring is maintained at aslight positive potential, although this is not critical and this ringmay be left to float and assume the potential of the beam, if desired.The specimen support frame is maintained at a positive 4 to 10kilovolts. This can also be modulated with an RF signal at an amplitudeof approximately 25 to 100 volts rms which serves to develop acontrolled plasma that periodically discharges the plastic or othernonconducting material of the specimen substrate. The lenses or otherproducts to be filmed are mounted in clips secured to the support frame.As an alternative to using a controlled plasma for discharging thesubstrate, isotope bodies may be mounted near the support frame fordischarging the plastic substrate by radioactive bombardment. Thecollector screen is also maintained at a positive potential of from 4 to10 kilovolts, thus providing a strong positive force drawing thenegatively ionized beam particles toward the specimens being bombarded.

It has also been found possible to develop a beam which results in filmdeposition and implantation by reversing the polarity of potentialsapplied to the various elements of the structure. In such event, ofcourse, the effectiveness of the ionizing elements is limited but theaccelerating, beam shaping and directing, and collecting elementsoperate with positive ions essentially as described for negativelyionized particles.

In alternative embodiments of the invention, various types andconfigurations of accelerating and ionizing structures may be employed.One such structure utilizes a series of vertical vanes fixed to thevarious horizontal rings by insulator mounts. The vanes are preferablyof stainless steel and fashioned with all surfaces made extremelysmooth, as by electropolishing, except the inner edge which is sharpenedto an extreme degree. As explained previously, the succeeding ringsincrease in diameter and the vanes are angled along their inner sharpedges to match the gradient of ring inner diameter. The shape of suchaccelerating vanes influences the rate of acceleration of the beamparticles. It may also be related to the shape of the specimen beingcoated. The shape of the beam may be varied by using rings which areelliptical or which present other shapes rather than circular.

Still another alternative arrangement of the accelerating ionizingstructure may utilize the stacked rings as first described but with theion emitting rings being fashioned with extremely sharp inner edgesinstead of having the needles mounted thereon as heretofore described.Still another embodiment may utilize a series of tubular rings with theaccelerating rings being rounded and polished while the electron emitter(ionizing) tubular elements are provided with a radially inward knifeedge.

The potentials applied to the various elements of the acceleratingstructure may be stepped and varied as desired. A varying effect on theshape, density and velocity of the beam can be achieved by varying thepotentials of the accelerating/ionizing structure as a function ofdistance from the emitter, for example. As already mentioned, other beamshaping and directing structures may be employed utilizing magneticfield control of beam shape and particle distribution.

Various arrangements and configurations of accelerating and beamdirecting elements may be employed to separate different particles inthe beam so that bombardment of the specimens occurs only with theparticles of desired size and velocity. Particular arrangements inaccordance with the invention include structure for developing orientedmagnetic fields which curve the desired particles along selected pathsto the specimens while other particles that might have a deleteriouseffect upon the specimens being bombarded are directed along paths whichimpact shields or otherwise miss the specimens altogether.

The benefits provided by the present invention are particularly usefulin developing suitable low-cost lenses for eyeglasses and otherapplications from materials and fabrication processes formerlyunsuitable. For example, it now becomes practical to form lenses byinjection molding processes with the lenses in the final fabricationstep being coated with films implanted by means of the presentinvention.

Moreover, arrangements in accordance with the present invention may beused for implanting films on substances and articles other than plasticlenses. For example, one or a plurality of beam ionizing andaccelerating arrangements in accordance with the present invention maybe used on a mass production basis to implant a film having the desiredproperties of hardness, resistance to abrasion, and the like on a thinsheet of plastic or other material suitable for lamination with othersheets of plastic or the like to develop a desired combination ofproperties for an overall article. Such a laminated article may comprisean automobile windshield, for example, with the principal layer of thearticle being a thicker sheet of plastic having desirable properties ofresistance to breakage and the like with the outer surfaces beingcovered with thin laminations of plastic implanted with a film inaccordance with the present invention. The resultant article develops,by virtue of the implanted film, the necessary properties of hardnessand resistance to surface abrasion which are not provided by the innersheet constituting the principal material of the article.

Mass production of such a film may be accomplished by feeding a thinsheet passing between respective storage rolls through an evacuatedchamber in which the beam accelerating and ionizing structures of thepresent invention are located. It may also be possible to treat fabricsof various type in similar fashion. It has been found that theimplantation of a particular material as a film has a beneficial resultinsofar as improvement of fire resistant or fire retardant properties isconcerned. It is believed that the implantation of such a film tends toprevent oxidation by keeping air from reaching the combustible materialunderneath. It may be possible to treat fabrics in such fashion todevelop fire retardant properties. Materials which are useful for thispurpose comprise minerals which are non-combustible and which present avery small temperature coefficient of expansion, thus permitting thefilm to avoid rupture and remain intact as a protective coating over aconsiderable temperature range. Where multiple constituents of theprotective film are present, they may be selected to compensate fortheir respective temperature coefficients so that the coefficient ofexpansion overall is approximately stabilized. Thus, the application ofheat does not have the effect of fracturing the implanted film. As longas the implanted film, which itself is non-combustible, maintains itsintegrity, the oxidizable material underneath is prevented fromcombination with oxygen.

DESCRIPTION OF THE DRAWING

A better understanding of the invention may be had from a considerationof the following detailed description, taken in conjunction with theaccompanying drawing, in which:

FIG. 1 is a perspective view of a system in accordance with the presentinvention;

FIG. 2 is a perspective view of particle bombardment apparatus inaccordance with the invention within the vacuum chamber shown in FIG. 1,with the cover removed;

FIG. 3 is a perspective view of one particular arrangement of theionizing and accelerating structure utilized in the apparatus of FIG. 2;

FIG. 4 is a plan view of another type of accelerator structure which maybe utilized in the arrangement of FIG. 2;

FIG. 5 is a sectional view, taken along the line 5--5 of FIG. 4;

FIG. 6 is a schematic plan view of an accelerator structure for use inapparatus of FIG. 2;

FIG. 7A is a section taken along the line 7--7 of FIG. 6, showingdetails of another type of accelerator structure;

FIG. 7B is a sectional view taken along the line 7--7 of an alternativeaccelerator structure;

FIG. 8 illustrates a particular product produced in accordance with theinvention;

FIG. 9 is a combination schematic and block diagram of a further systemin accordance with the invention;

FIG. 10 is a view of elements of a particular product fashioned inaccordance with the invention;

FIG. 11 is a view in section of another product of the invention;

FIGS. 12, 13 and 14 are block diagrams illustrating various methods inaccordance with the inventions;

FIG. 15 is an elevational view, partially in section and broken away, ofanother arrangement in accordance with the invention for use in thesystem of FIG. 1; and

FIG. 16 is a similar view of yet another arrangement in accordance withthe invention.

Description of the Preferred Embodiments

As is shown in FIG. 1, a complete system 10 in accordance with theinvention may comprise a high voltage power supply 12, a high vacuumsystem 14 and an RF power supply 16. The vacuum system 14 comprises abell jar housing or cover 18 having one or more viewing windows 19 and avacuum control console 20. Suitable interconnections between the variouscomponents of the overall system are provided via cables 22 and 24.

FIG. 2 depicts a bombardment apparatus mounted within the housing 18 ofthe vacuum system 14 of FIG. 1. The apparatus 15 is shown comprisingupstanding frame support rods 30 mounted to a base plate ring 32 inposition on the control console table 20. Recessed within the base platering 32 is an electron beam gun emitter 34, shown partially broken awayin section. Such a unit may comprise a Model 2" SFIH-270° electron beamsource with a Model CV-14 power supply, both of Airco Temescal Divisionof Air Reduction Company, Inc. and, as represented in FIG. 2, may bewater-cooled by means of tubes 36 and have a centrally located targetregion 38 in which slug 40 of material to be evaporated is positioned. Afilament (not shown) is positioned within the cavity 42. Suitablemagnetic field generating coils are located within the structureadjacent the cavity 42. Various leads 44 are provided for carryingcurrent to the filament and to the field generating coils. In operationof the electron beam gun emitter 34, electrons are emitted by thefilament within the cavity 42 and directed outward and downward upon thetarget slug 40 under the influence of the generated electromagneticfield where they bombard and heat the slug 40 to cause emission ofionized molecular particles therefrom. A pivotable shutter 46,controllable from outside the vacuum housing, is provided to eitherblock the cloud of emitted ionized particles or, alternatively whenpivoted out of the way, to permit the ionized particles to respond tothe field of the accelerating structure 48.

A specimen support or mounting frame 50 is shown mounted by means ofinsulators 52 atop the support rods 30. It is this frame 50 upon whichthe various articles, such as plastic lenses, may be secured fordeposition of the film. A collector screen 54 is shown in position abovethe frame 50. It will be understood that the collector screen 54 isactually mounted to the top of the housing 18 (FIG. 1) but it is shownin position here as it is normally located when the housing 18 is inposition, for a more complete understanding of the apparatus. Thepotential of the screen 54 may be determined by connections (not shown)to the inside of the housing 18.

The accelerating/ionizing structure 48 is suspended from the supportrods 30 by means of wires 60 and insulators 62. The details of theaccelerator/ionizer 48 are better shown in FIG. 3. It will be seen tocomprise a plurality of flat rings, increasing in both inner and outerdiameter from bottom to top. The first, third and fifth rings 66 serveas guard rings and principally serve to isolate the field of theintermediate ionizing or emitting rings 68, although they may contributeto the electric field for particle acceleration and direction. Anaccelerating ring 70 is the uppermost ring in the structure 48. Thus,six rings are shown in the structure, although a greater or lessernumber may be provided if desired. Adjacent rings are separated from oneor another by means of insulators such as 72. The emitter rings areprovided with a plurality of needles 74 spaced generally equidistantlyabout the rings 68, and soldered thereto, as by silver solder. Thepoints of the needles 74 are sharpened to a fine degree and pointradially inward. Thus, the points of the needles 74 readily emitelectrons under the influence of an electric field which serves tofurther ionize the modecular particles that are being acted upon by theaccelerator structure 48 and drawn toward the specimen/collector regionby the positive potentials applied thereto.

The potential of the various elements of the apparatus of FIG. 2 may becontrolled by means of conductors and feed-through insulators 80extending through the base plate ring 32. Thus, a conductor 82 isconnected to the specimen frame 50. A conductor 84 is connected to alower wire 60 to control the potential of the accelerating ring 70.Conductors 86 extend to respective ones of the guard rings 66, while thepotential of the emitter rings 68 is controlled by conductors 88. Theseare connected to the associated high voltage power supply 12 and RFpower supply 16 (FIG. 1).

In one particular mode of operation of the apparatus, radioactiveisotope blocks 90 may be utilized to discharge the build-up of surfacecharge on the specimens being filmed through radioactive bombardment.Such radioactive isotope blocks may also be suitably positioned at otherpoints within the housing 18 in locations suitable for effectivelydischarging the specimens, if desired. Alternatively microwave RF energymay be beamed at the specimens from suitably positioned slotted lossywave-guide elements to produce a local plasma for discharging surfacecharge.

FIGS. 4 and 5 illustrate respectively plan and sectioned elevationalviews of one alternative type of accelerator/ionizing structure whichmay be substituted for that shown in FIGS. 2 and 3. This structure,designated 48A, comprises a plurality of rings 101, of which three areshown, electrically isolated from one another and from interconnectingvertical vanes 102 by means of insulators 103. The vanes 102 are angledto follow the contour of the inner diameters of the respective rings 101and are sharpened to a fine razor edge along this portion of the vanes102. The remainder of the structure is smooth, as by electropolishing.Thus the vanes 102 serve to emit electrons copiously along theirsharpened inner edges under the influence of an electric field. Suitableconnections (not shown) may be provided to control the potentials of thevanes 102 and rings 101.

FIG. 6 is a schematic plan view of accelerating structure 48 and FIGS.7A and 7B are partial sectional elevations of alternative arrangementsfor the structure 48. FIG. 7A illustrates a plurality of tubular ringsof which the emitter rings 104 have been fashioned with an extended andsharpened inner edge. The remainder of the rings 106 are perfectlyrounded and electropolished to develop a smooth surface. The rings 104under the influence of the applied electric field serve to dischargeelectrons inwardly from the sharpened inner edges.

FIG. 7B represents a structure similar to that shown in FIG. 3, exceptthat the needles 74 have been eliminated and the two emitter rings 68Ahave been provided with a sharply honed inner edge to accomplish theemission of electrons inwardly under the influence of the electricfield. The remainder of the rings 68 are smoothed, as byelectropolishing, as are the other surfaces and edges of the rings 68apart from the sharpened inner edge thereof.

Other accelerator and ionizing structural configurations may be devisedto accomplish the results achieved by the accelerator/ionizer structure48 and alternative arrangements shown and described herein. Inparticular, the structure may be substituted or modified by theinclusion of apparatus for generating magnetic fields, either in placeof or in addition to the electric fields generated by certain of theelements herein shown, in order to accomplish the desired result ofdirecting and shaping the particle beam to fit the particular specimenon which the film is being deposited.

FIG. 8 is a representation of a particular lens 110 which has beenespcially coated in the apparatus shown and described herein. Lens 110on its left half 112 and the small circles 114 has been coated with animplanted film comprising principally minerals such as those referred tohereinabove selected for their properties of hardness, elasticity, heatresistance, and optical clarity. Except for the small circular areas114, the right half 116 is uncoated. This was accomplished by firstmasking the right half 116 with a perforated foil layer beforeimplanting the film. As a test, the lens 110 was then rubbed withvarious abrasive materials, including emery paper and steel wool. Thecoated areas 112 and 114 were unmarked by these abrasive materials andthe lens remains clear and transparent in these areas. Over theremainder of the right half 116, however, the lens was severelyscratched to the point where it was no longer transparent, as indicatedby the stippling shown thereon. Similar experiments with soft lensescoated by other methods known in the art served to scratch and mar thelens face but did not affect the films and filmed lenses produced by thepresent invention.

Various other uses besides the coating of eye glass lenses and the likemay be realized from the practice of the present invention. FIGS. 9 and10 illustrate another extensive area of use where the present inventionwill be most important. FIG. 9 illustrates a continuous system utilizinga plurality of particle bombardment units of the present inventionarranged for a continuous film deposition process to implant a hard filmon a cellulose plastic sheet. Facilities are known in the art fordeveloping and maintaining a high vacuum chamber through whichcontinuous materials may be fed for vacuum processing. The combinationschematic and block diagram of FIG. 9 is intended to represent such asystem. It is shown comprising a large chamber 120 through which aplastic sheet 122 is fed between rolls 124 and 126 at opposite ends ofthe chamber. Successive vacuum barriers 128 are provided at each end ofthe chamber 120. The film may be fed through suitable sealingarrangements 130, here represented as rollers between which the sheet122 passes in going between outside ambient pressure and the high vacuuminside the chamber 120. Air passages or ports 132 are provided toconnect the various regions within the chamber 120 with a plenum chamber134 which is maintained at a high vacuum by an associated vacuum system138. Alternatively the reels 124, 126 may be positioned within thechamber 120, in which case the need for the sealing elements foradmitting the plastic 122 through the chamber walls is unnecessary.Within the chamber 120 and adjacent the sheet 122 which is supported onrollers or guides 136 is shown a plurality of units 15 (FIG. 2) mountedon a base 148. These units 15 are shown as being connected to a powersupply unit 139 which may include both the high voltage power supply andRF generator supply used in the system of the invention.

In operation of the system represented in FIG. 9, the sheet 122 istransferred from roll 124 to roll 126, passing through the vacuumchamber 120 and past the ionized particle deposition units 15. One ormore of the units 15 may be operated to implant the desired film on oneor both sides of the sheet 122 so as to develop the film in the desiredareas and to the desired thickness. If deposition on both sides of thesheet 122 is desired, it can easily be arranged, either by mountingadditional units 15 on opposite sides of the sheet (possibly by usingdeflecting fields to develop the desired particle trajectories) orsimply by doubling back the sheet 122 so that it traverses one or moreof the units 15 with the opposite side of the sheet in position to bebombarded by the ionized particles therefrom.

An outstanding benefit of implanting film on plastic sheet in thisfashion is the opportunity which develops for fabricating a variety ofarticles which have heretofore been limited to fabrication from glassbecause of the need for surface protection by providing extremeresistance to abrasion. One such item is the automobile windshield. Suchis represented in FIG. 10 as being formed of plastic sheet, preferablyinjection molded to a suitable thickness and shape, to which a sheet142, cut from a sheet 122 which has been implanted with a hard film inaccordance with the invention as described in connection with FIG. 9,may be bonded. In FIG. 10, only one such sheet 142 is shown inconjunction with the base layer 140, although it will be understood thata sheet 142 may be provided on each side of the base layer 140.

FIG. 11 represents a cross-section of an article, such as the windshieldof FIG. 10 or an injection-molded lens, for example, in which a baselayer 150 is laminated between two layers 152. Each of the layers 152 isimplanted with a hardened film in the manner described hereinabove alongits outer surface. Thus, the laminated structure will provide thedesired combination of toughness and resilience that may correspond tothe base layer 150 and still provide the resistance to abrasion alongall surfaces that are subject to abrasive forces as is provided by theprotective film implanted in the manner described herein. One method ofproducing such an article is illustrated in FIG. 12. The moregeneralized methods of operating apparatus in accordance with theinvention as described in conjunction with FIGS. 1-7 and 9 areillustrated in FIG. 13.

Thus far the invention has been described in the context of depositionof a clear transparent film on a plastic substrate. However, it will beunderstood that other films may be deposited and that the substrate neednot necessarily be plastic or, indeed, non-conducting. Various materialsor compositions may be used as a source of the particles for deposition.One type of particular interest for sunglasses and windows for filteringthe sun's rays is the deposition of a colored film. This may beaccomplished by the inclusion of the oxides or other substances whichimpart the desired color to the film as deposited. Since the colors andtints achieved thereby have a tendency to fade, proportionally onexposure to ultraviolet light, it is desirable to implant a film of adeeper shade, color or tint than that which is ultimately desired andthereafter by exposure to ultraviolet rays or a similar treatment fadethe deposited film to the intended hue. With controlled rates ofdeposition of a colored film, the ultraviolet rays which are present inthe plasma during the deposition process may develop the desired fadingso that the ultimate level of tinting is already present when thedeposition process is completed. Such methods are illustrated in FIG.14.

An alternative arrangement in accordance with the present invention foruse in the system of FIG. 1 is illustrated in FIG. 15, which is apartial elevational view showing the details of particular features,partially in section and partially broken away. In FIG. 15, apparatus150 is shown having many of its basic structural elements similar to thestructure of the apparatus 15 of FIG. 2; and where correspondingelements of structure are shown, the same reference numerals areemployed. Thus, the apparatus 150 is shown comprising a base 32 mountedon a table 20, a combination accelerating and ionizing structure 48suspended by wires 60 and insulators 62 from support members 30, ashutter 46 mounted for pivotal movement above the base 32, and a belljar cover 18a corresponding to the bell jar 18 of the vacuum apparatusof FIG. 1.

In the configuration of FIG. 15, while the ionized particle beam isgenerated, accelerated and ionized in the same fashion as with theapparatus of FIG. 2, the beam is subsequently directed through a curvedpath to impact the mounted specimens. The purpose of directing the beamin such fashion is to achieve a separation of particles of various sizesand weights, thus avoiding a deleterious effect on the specimen beingcoated which might be caused by the impacting of larger particles thatare sputtered off the material which is the source of the filmparticles. It has been found that the impact upon the specimens beingfilmed of relatively large particles tends to produce pitting of theimplanted film. As a consequence, the film is fractured or the largerparticles are embedded in the specimen and there is a tendency forabsorption of moisture with a consequent lifting of film in the vicinityof the pits. In an extreme case the larger particles may developundesirable surface irregularites. It has been found that the tendencyto emit larger particles along with the smaller ones which are desiredfor the implanting process is diminished if the material comprising thesource of the film is heated to a molten form before emission isinitiated. However, applying this much heat to the system has an adverseeffect in cases where the specimens are plastic or some other softmaterial since the heat tends to soften and melt the specimens andspoils the entire process.

A preferable arrangement for overcoming this problem is represented inFIG. 15 wherein the apparatus 150, in addition to comprising theelements already mentioned, includes means for establishing particularlyoriented magnetic fields for directing the smaller particles to thespecimens that are placed out of the path of the larger particles. Thisapparatus is shown additionally comprising a cylinder 164 containingmagnetic field coils 165 for establishing a vertically directed magneticfield. The cylinder 164 is suspended from the support rods 30 by meansof wires 160 and insulators 162. Above the cylinder 164 is shown asecond magnetic field means 166 for establishing a magnetic field whichis horizontally directed. Means 166 may comprise individual magnets 168which may be in the form of permanent magnets or the magnets 168 may bethe pole pieces of electromagnetic coil magnets. In one configuration,means 166 may be in the form of a generally flat plate mounted to thewall of the housing 18a on the far side thereof, with a correspondingmagnetic field means of opposite magnetic polarity (not shown) on thenear side of the beam path through the center of the housing 18a.

Above the magnetic field producing apparatus is an arrangement forsuspending the specimens about the sides of the housing 18a. Thismechanism is represented as a cylinder 170 having an extended upper lipadapted to be supported on a ring 172 by means of ball bearings 174 topermit rotation of the cylinder 170. A motor 176 with a drive roller 178bearing against the cylinder 170 serves to drive the cylinder 170 inrotation within the housing 18a. Specimens in the forms of lenses 180are shown positioned on mounting racks 182 pivotably mounted in supports184. The racks 182 are arranged to be pivoted through 180° at aparticular point in the cycle of rotation of the cylinder 170 in orderto rotate the lenses 180 relative to the cylinder 170 so that they maybe coated on both opposite surfaces. As shown in FIG. 15, this pivotingmechanism comprises a block 186 having a rod 188 extending to engage atrip lever 190 at the lower ends of the racks 182. Thus as eachindividual rack 182 passes the rod 188, the trip lever 190 is engaged bythe rod 188 and caused to rotate so as to turn the lenses 180 around andexpose the other side to bombardment on further rotation of the cylinder170.

In the operation of the apparatus of FIG. 15, emitted particles areaccelerated and ionized by means of the apparatus 48 as alreadydescribed in connection with FIG. 2. As the particle beam passes throughthe apparatus 48, the larger particles pick up a lesser negative chargein proportion to their mass than do the smaller particles. In fact, theparticles may have a positive charge upon emission which, in someinstances, is not even neutralized by the emitted electrons duringpassage of the particles through the apparatus 48. As is known, theballistic trajectory of a charged particle through a magnetic field maybe dependent on the charge-to-mass ratio. Particles having a largercharge-to-mass ratio are deflected more by an orthogonal magnetic fieldthan particles which have zero net charge or a smaller charge-to-massratio. Thus, the magnetic field directing and deflecting means of FIG.15 serve to separate the particles which are larger than desired andthose which are inadequately ionized from the particles of proper sizeand ionization to produce the desired film implantation on the lensspecimens 180.

For apparatus such as is shown in FIG. 15, a collector and suitablesurface charge discharging means may be positioned across the topunderneath the dome of the housing 18a in the manner indicated in FIG.2. Such a collector, in addition to being effective as an elementestablishing an electrostatic field, may also serve to collect and trapthe charged particles of larger size or lesser charge-to-mass ratiowhich are not directed by means of the magnetic field of the magneticfield means 166 to the specimens 180. As an alternative to thearrangement as depicted in FIG. 15, the specimens may be mounted in themanner shown in FIG. 2 with magnetic field deflecting means such as abaffle being provided to cause the particles to follow a dog-leg curvedpath which ultimately directs the appropriate particles to the specimenwhile deflecting or trapping the undesired particles outside the regionof the specimens being implanted.

As another alternative to the arrangement represented in FIG. 15 whereinthe specimens are physically revolved by the cylinder 170 about theinterior of the housing 18a during the film deposition process, theposition of the specimens 180 may be fixed by holding the cylinder 170stationary and the magnetic field of the magnetic field means 166 may berotated to cause the particle beam to sweep the specimen area. In suchcase, the magnetic field means 166 may itself comprise a cylindricalring with the individual magnet field elements 168 being selectivelymagnetized by electromagnetic fields established by selective andsuccessive energization of the respective electromagnetic coils todevelop a horizontal magnetic field which rotates in controlled fashionin a plane generally orthogonal to the longitudinal axis of theapparatus 150. Such a swept field may selectively film any particularspecimen as desired. At the same time it is effective in the manneralready described at separating the desired particles from the undesiredparticles in order to provide an improved resultant filmed product.Also, if desired, the structure comprising the mounting racks 182 may beelectrostatically charged so that these racks 182 serve additionally asa collector to attract the charged particles passing through theaccelerating and ionizing structure 48 and the magnetic field means 164,166.

Still another embodiment of the invention is represented in FIG. 16which shows apparatus 200 such as may be employed in the system ofFIG. 1. Apparatus 200 is similar to that shown in FIG. 2 with certainnotable modifications. As shown in FIG. 16, the apparatus 200 comprisesthe vacuum chamber within a housing 18a having a table 20, a base 32, aparticle emitter 34, a shutter 46 and the ionizing, accelerating anddirecting structure 48. The elements 34, 46, and 48 are positionedoff-center within the vacuum chamber of the apparatus 200. Above theelements 34, 46 and 48, and aligned therewith, is a particle divertingand directing structure 202 suspended from support rods 204 by means ofwires 206 and insulators 208. As shown in FIG. 16, the structure 202includes a plurality of toroidal ring magnets 210 mounted within anouter housing or baffle 212. The respective ring magnets 210 aresuccessively positioned along the intended path of the selected ionizedparticles and so oriented as to direct the particles by means of anelectromagnetic field from the vicinity of the apparatus 48 upward andsideways to establish a stream of ionized particles generally centrallylocated and symmetrically disposed about the longitudinal axis of thehousing 18a. The baffle or shield 212 is so arranged as to prevent anyline-of-sight path from the structure 48 to the specimens above theapparatus 200. In this arrangement in accordance with the invention, theupper portion of the apparatus may correspond to the upper part of FIG.2 with the specimens symmetrically disposed across the upper end of thechamber 18a. In this arrangement, the particles which do not have theappropriate velocities and charge-to-mass ratio will not follow the samepath through the apparatus 202 as do the selected particles, but insteadwill tend to impact the baffle or shield comprising the housing 212 andthus be removed from the stream of ionized particles directed toward thespecimens at the top of the apparatus.

Although FIG. 16 shows the diverting and directing apparatus 202 asincluding a plurality of ring magnets 210, it will be understood thatthis structure may be formed of a single solenoidal coil in place of theindividual magnets 210. Alternatively a plurality of permanent magnets,suitably fixed in a series of rings, may be used as the magnets 210.Such an arrangement has the advantage of developing the desiredparticle-diverting field without the application of electrical power,thus reducing the power requirements of the apparatus 200 and avoidingthe heat otherwise generated within the housing 18a by the electromagnetsystem.

Apparatus in accordance with the present invention may also be utilizedto implant metal surfaces with desired compounds. Certain compounds mayhave the effect of changing the surface properties of the metallicarticle, similar to the hardening provided for plastic lenses and thelike already described. In other circumstances, apparatus in accordancewith the present invention may be utilized to implant surface films onselected portions of semiconductors in order to facilitate thefabrication of entire solid state circuits on single semiconductorchips. Various other applications of the methods and apparatus of thepresent invention will occur to those skilled in the art withoutdeparting from the concepts of the invention.

Thus, there have been described and shown herein various particulararrangements in accordance with the present invention which illustratethe application thereof to a variety of uses. Variations of thestructures shown and described herein, all within the basic concept ofthe invention, will occur to those skilled in the art. For example,other configurations of ionizing elements may be employed, as for anexample the use of specific electron guns for directing electrons intothe particle stream for further ionization thereof.

Although there have been described above specific methods and apparatusfor depositing film on a substrate, and products produced thereby, inaccordance with the invention for the purpose of illustrating the mannerin which the invention may be used to advantage, it will be appreciatedthat the invention is not limited thereto. Accordingly, any and allmodifications, variations or equivalent arrangements which may occur tothose skilled in the art should be considered to be within the scope ofthe invention.

What is claimed is:
 1. A product having at least a portion thereofproduced by the bombardment of a substrate by ionized molecularparticles of a selected material comprising:a specimen substrate; a filmdeposited on and implanted in said substrate, said implantationoccurring to a depth of from severl hundred angstroms to severalmicrons.
 2. A product in accordance with claim 1 wherein saidimplantation occurs to a depth of approximately one micron.
 3. A productin accordance with claim 1 wherein the deposited film is built up to athickness of approximately two microns above the substrate surface.
 4. Aproduct in accordance with claim 1 wherein the product is an eyeglasslens comprising a plastic substrate and a transparent film depositedthereon.
 5. A product in accordance with claim 4 wherein said filmcomprises a mineral selected for properties of hardness, elasticity,heat resistance, and optical clarity.
 6. A product in accordance withclaim 5 wherein the film further includes trace impurities of otherselected minerals.
 7. A product in accordance with claim 6 wherein saidtrace impurities include materials imparting a selected tint to saidlens.
 8. A product in accordance with claim 1 wherein said substratecomprises a sheet of flexible plastic material.
 9. A product inaccordance with claim 8 further including a sheet of relatively toughmaterial having a relatively soft surface by itself laminated between apair of said flexible sheets, each having a hardening film on its outersurface implanted by a deposition process, said sheets in combinationcomprising a window.